This invention relates generally to the field of semiconductor integrated circuits, and, more particularly, to negative switch circuits.
Various integrated circuits use negative voltages to perform certain operations. For example, flash memory devices may use a negative voltage as high as −9 volts to erase data stored on the flash memory cells. By maximizing the amount of negative voltage that can be applied to the flash memory cells, the overall performance of the flash memory device is typically improved. The performance of flash memory devices may be improved by reducing the amount of time it takes to erase the data stored in the flash memory cells or by reducing the charge loss in the flash memory cells. The flash memory may also use relatively low negative voltages, as low as −0.25 volts for example. One use of relatively lower negative voltages is to bias deselected word lines.
These negative voltages may be generated by negative charge pumps. Since the negative voltages are only needed at specific times, negative switches may be used to switch the supplied voltages.
Thus, there is a need for other ways to provide negative voltage switching.